fix: tweak spacing in send asset picker

[BZahory]

Description

The token symbol send page's asset picker is not vertically aligned with other dropdowns on the page. This PR removes an unneeded margin introduced in #25470.

Related issues

Fixes:

Manual testing steps

1. Go to send page
2. Ensure asset picker is spaced correctly and vertically aligned with other components

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.60%. Comparing base (699ddcc) to head (9604e0d).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #25576   +/-   ##
========================================
  Coverage    69.60%   69.60%           
========================================
  Files         1364     1364           
  Lines        48172    48172           
  Branches     13291    13291           
========================================
  Hits         33526    33526           
  Misses       14646    14646           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[metamaskbot]

Builds ready [9604e0d]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • offscreen: 0
  • ui: 0, 1, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (152 ± 159 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	65	291	119	51	25
		domContentLoaded	8	97	34	21	10
		load	41	1588	152	331	159
		domInteractive	8	97	34	21	10

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: -14 Bytes (-0.00%)
• common: 0 Bytes (0.00%)